The gene concept has been one of the hallmarks in 20th century history of science, but is currently shrouded in controversy, given the difficulty for understanding the structural limits of the gene or the meaning of its function. Once conceived according to the so-called classical molecular concept, as a stretch of DNA coding for a functional product, which can be a single polypeptide chain or a functional RNA molecule, the gene amounted to a structural unit clearly delineated in the genome, to which one could ascribe a clear function. Currently, it is not a simple task to delimit what is a gene or explain how it functions. The gene concept is challenged by many problems. Consequently, a number of proposals for reconceptualizing the gene appeared in recent years, in the so-called postgenomic era. In this paper, I will discuss such proposals that emerged in the last 10 years, particularly focusing on Scherrer and Jost’s genon theory. From this discussion, I will derive some ideas regarding the understanding of what is a gene and how a gene functions in the postgenomic era, particularly focusing on the idea of a dynamic, systemic gene. Moreover, I will address results from previous studies on how genes and their functions are discussed in school science knowledge, in order to examine what are the consequences of the treatment of genes along schooling for citizenship education in a society increasingly affected by discourses about genes and genetic technologies. In particular, I will argue that things go seriously wrong in genetics education when not informed by historical and philosophical approaches to the gene.